Staphylococcus aureus(S. aureus) is a common pathogenic bacterium in animal husbandry that can cause diseases such as mastitis, skin infections, arthritis, and other ailments. The formation of biofilms threatens and e...Staphylococcus aureus(S. aureus) is a common pathogenic bacterium in animal husbandry that can cause diseases such as mastitis, skin infections, arthritis, and other ailments. The formation of biofilms threatens and exacerbates S. aureus infection by allowing the bacteria to adhere to pathological areas and livestock product surfaces, thus triggering animal health crises and safety issues with livestock products. To solve this problem, in this review, we provide a brief overview of the harm caused by S. aureus and its biofilms on livestock and animal byproducts(meat and dairy products). We also describe the ways in which S. aureus spreads in animals and the threats it poses to the livestock industry. The processes and molecular mechanisms involved in biofilm formation are then explained. Finally, we discuss strategies for the removal and eradication of S. aureus and biofilms in animal husbandry, including the use of antimicrobial peptides, plant extracts, nanoparticles, phages, and antibodies. These strategies to reduce the spread of S. aureus in animal husbandry help maintain livestock health and improve productivity to ensure the ecologically sustainable development of animal husbandry and the safety of livestock products.展开更多
Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to expl...Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to explore more effective approaches for the treatment of MRSA biofilm infections.Methods:Herein,an interfacial functionalization strategy is proposed by the integration of mesoporous polydopamine nanoparticles(PDA),nitric oxide(NO)release donor sodium nitroprusside(SNP)and osteogenic growth peptide(OGP)onto Ti implants,denoted as Ti-PDA@SNP-OGP.The physical and chemical properties of Ti-PDA@SNP-OGP were assessed by scanning electron microscopy,X-ray photoelectron spectroscope,water contact angle,photothermal property and NO release behavior.The synergistic antibacterial effect and elimination of the MRSA biofilms were evaluated by 2′,7′-dichlorofluorescein diacetate probe,1-N-phenylnaphthylamine assay,adenosine triphosphate intensity,O-nitrophenyl-β-D-galactopyranoside hydrolysis activity,bicinchoninic acid leakage.Fluorescence staining,assays for alkaline phosphatase activity,collagen secretion and extracellular matrix mineralization,quantitative real‑time reverse transcription‑polymerase chain reaction,and enzyme-linked immunosorbent assay(ELISA)were used to evaluate the inflammatory response and osteogenic ability in bone marrow stromal cells(MSCs),RAW264.7 cells and their co-culture system.Giemsa staining,ELISA,micro-CT,hematoxylin and eosin,Masson's trichrome and immunohistochemistry staining were used to evaluate the eradication of MRSA biofilms,inhibition of inflammatory response,and promotion of osseointegration of Ti-PDA@SNP-OGP in vivo.Results:Ti-PDA@SNP-OGP displayed a synergistic photothermal and NO-dependent antibacterial effect against MRSA following near-infrared light(NIR)irradiation,and effectively eliminated the formed MRSA biofilms by inducing reactive oxygen species(ROS)-mediated oxidative stress,destroying bacterial membrane integrity and causing leakage of intracellular components(P<0.01).In vitro experiments revealed that Ti-PDA@SNP-OGP not only facilitated osteogenic differentiation of MSCs,but also promoted the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2-phenotype(P<0.05 or P<0.01).The favorable osteo-immune microenvironment further facilitated osteogenesis of MSCs and the anti-inflammation of RAW264.7 cells via multiple paracrine signaling pathways(P<0.01).In vivo evaluation confirmed the aforementioned results and revealed that Ti-PDA@SNP-OGP induced ameliorative osseointegration in an MRSA-infected femoral defect implantation model(P<0.01).Conclusions:Ti-PDA@SNP-OGP is a promising multi-functional material for the high-efficient treatment of MRSA infections in implant replacement surgeries.展开更多
Slightly acidic electrolyzed water(SAEW)has proven to be an efficient and novel sanitizer in food and agriculture field.This study assessed the efficacy of SAEW(30 mg/L)at 40℃on the inactivation of foodbome pathogens...Slightly acidic electrolyzed water(SAEW)has proven to be an efficient and novel sanitizer in food and agriculture field.This study assessed the efficacy of SAEW(30 mg/L)at 40℃on the inactivation of foodbome pathogens and detachment of multi-resistant Staphylococcus aureus(MRSA)biofilm.Furthermore.the underlying mechanism of MRS A biofilm under heated SAEW at 40℃treatment on metabolic profiles was investigated.The results showed that the heated SAEW at 40℃significantly effectively against foodbome pathogens of 1.96-7.56(lg(CFU/g))reduction in pork,chicken,spinach,and lettuce.The heated SAEW at 40℃treatment significantly reduced MRS A biofilm cells by 2.41(lg(CFU/cm^(2))).The synergistic effect of SAEW treatment showed intense anti-biofilm activity in decreasing cell density and impairing biofilm cell membranes.Global metabolic response of MRSA biofilms,treated by SAEW at 40℃,revealed the alterations of intracellular metabolites,including amino acids,organic acid,fatty acid,and lipid.Moreover,signaling pathways involved in amino acid metabolism,energy metabolism,nucleotide synthesis,carbohydrate metabolites,and lipid biosynthesis were functionally disrupted by the SAEW at 40℃treatment.As per our knowledge,this is the first research to uncover the potential mechanism of heated SAEW treatment against MRSA biofilm on food contact surface.展开更多
Staphylococcus aureus is a serious foodborne pathogen threatening food safety and public health.Especially the emergence of methicillin-resistant Staphylococcus aureus(MRSA)increased the difficulty of S.aureus treatme...Staphylococcus aureus is a serious foodborne pathogen threatening food safety and public health.Especially the emergence of methicillin-resistant Staphylococcus aureus(MRSA)increased the difficulty of S.aureus treatment.Staphyloxanthin is a crucial virulence factor of S.aureus.Blocking staphyloxanthin production could help the host immune system counteract the invading S.aureus cells.In this study,we first screened for staphyloxanthin inhibitors using a virtual screening method.The outcome of the virtual screening method resulted in the identification of eugenol(300μg/mL),which significantly inhibits the staphyloxanthin production in S.aureus ATCC 29213,S.aureus Newman,MRSA ATCC 43300 and MRSA ATCC BAA1717by 84.2%,63.5%,68.1%,and 79.5%,respectively.The outcome of the growth curve assay,field-emission scanning electron,and confocal laser scanning microscopy analyses confirmed that eugenol at the test concentration did not affect the morphology and growth of S.aureus.Moreover,the survival rate of S.aureus ATCC 29213 and MRSA ATCC 43300 under H_(2)O_(2) pressure decreased to 51.9%and 45.5%in the presence of eugenol,respectively.The quantitative RT-PCR and molecular simulation studies revealed that eugenol targets staphyloxanthin biosynthesis by downregulating the transcription of the crtM gene and inhibiting the activity of the CrtM enzyme.Taken together,we first determined that eugenol was a prominent compound for staphyloxanthin inhibitor to combat S.aureus especially MRSA infections.展开更多
Background:Staphylococcus aureus is responsible for the majority of skin and soft tissue infections,which are often diagnosed at a late stage,thereby impacting treatment efficacy.Our study was designed to reveal the p...Background:Staphylococcus aureus is responsible for the majority of skin and soft tissue infections,which are often diagnosed at a late stage,thereby impacting treatment efficacy.Our study was designed to reveal the physiological changes at different stages of infection by S.aureus through the combined analysis of variations in the skin microenvironment,providing insights for the diagnosis and treatment of S.aureus infections.Methods:We established a murine model of skin and soft tissue infection with S.aureus as the infectious agent to investigate the differences in the microenvironment at different stages of infection.By combining analysis of the host immune status and histological observations,we elucidate the progression of S.aureus infection in mice.Results:The results indicate that the infection process in mice can be divided into at least two stages:early infection(1–3 days post-i nfection)and late infection(5–7 days post-i nfection).During the early stage of infection,notable symptoms such as erythema and abundant exudate at the infection site were observed.Histological examination revealed infiltration of numerous neutrophils and bacterial clusters,accompanied by elevated levels of cytokines(IL-6,IL-10).There was a decrease in microbial alpha diversity within the microenvironment(Shannon,Faith's PD,Chao1,Observed species,Simpson,Pielou's E).In contrast,during the late stage of infection,a reduction or even absence of exudate was observed at the infected site,accompanied by the formation of scabs.Additionally,there was evidence of fibroblast proliferation and neovascularization.The levels of cytokines and microbial composition gradually returned to a healthy state.Conclusion:This study reveals synchrony between microbial composition and histological/immunological changes during S.aureus-i nduced SSTIs.展开更多
Sensitive detection of Staphylococcus aureus enterotoxin B(SEB)is of importance for preventing food poisoning from threatening human health.In this work,an electrochemical and colorimetric dual-signal detection assay ...Sensitive detection of Staphylococcus aureus enterotoxin B(SEB)is of importance for preventing food poisoning from threatening human health.In this work,an electrochemical and colorimetric dual-signal detection assay of SEB was developed.The probe(Ab2/AuPt@Fe-N-C)was bound to SEB captured by Ab1,where the Ab2/AuPt@Fe-N-C triggered methylene blue degradation and resulted in the decrease of electrochemical signal.Furthermore,the probe catalyzed the oxidation of 3,3’,5,5’-tetramethyl biphenyl to generate a colorimetric absorbance at 652 nm.Once the target was captured and formed a sandwich-like complex,the color changed from colorless to blue.SEB detection by colorimetric and electrochemical methods showed a linear relationship in the concentration ranges of 0.0002-10.0000 and 0.0005-10.0000 ng/mL,with limits of detection of 0.0667 and 0.1670 pg/mL,respectively.The dual-signal biosensor was successfully used to detect SEB in milk and water samples,which has great potential in toxin detection in food and the environment.展开更多
BACKGROUND The oral cavity harbors more than 700 species of bacteria,which play crucial roles in the development of various oral diseases including caries,endodontic infection,periodontal infection,and diverse oral di...BACKGROUND The oral cavity harbors more than 700 species of bacteria,which play crucial roles in the development of various oral diseases including caries,endodontic infection,periodontal infection,and diverse oral diseases.AIM To investigate the antimicrobial action of Cymbopogon Schoenanthus and Pelargonium graveolens essential oils against Streptococcus mutans,Staphylococcus aureus,Candida albicans,Ca.dubliniensis,and Ca.krusei.METHODS Minimum microbicidal concentration was determined following Clinical and Laboratory Standards Institute documents.The synergistic antimicrobial activity was evaluated using the Broth microdilution checkerboard method,and the antibiofilm activity was evaluated with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay.Data were analyzed by one-way analysis of variance followed by the Tukey post-hoc test(P≤0.05).RESULTS C.schoenanthus and P.graveolens essential oils were as effective as 0.12%chlorhexidine against S.mutans and St.aureus monotypic biofilms after 24 h.After 24 h P.graveolens essential oil at 0.25%was more effective than the nystatin group,and C.schoenanthus essential oil at 0.25%was as effective as the nystatin group.CONCLUSION C.schoenanthus and P.graveolens essential oils are effective against S.mutans,St.aureus,Ca.albicans,Ca.dubliniensis,and Ca.krusei at different concentrations after 5 min and 24 h.展开更多
[Objective] The effect of different culture conditions on type 5 capsular polysaccharide production of Staphylococcus aureus from diary cattle was studied to provide simple way for CP production and preparation and la...[Objective] The effect of different culture conditions on type 5 capsular polysaccharide production of Staphylococcus aureus from diary cattle was studied to provide simple way for CP production and preparation and laid foundation for carrying out new polysaccharide vaccine research. [Method] Staph-ylococcus aureus was isolated from milk sample of sick dairy cattle and capsular polysaccharide serotypes were identified. Type 5 capsular polysaccharide was cultured on BHI,solid columbia and mod110 culture media. Glucose and lactose were taken as carbon sources for every culture media in solid and liquid state. Therefore 9 different culture conditions were taken to study the effect of culture conditions on capsular polysaccharide production. [Result] Different culture conditions indicated that compared with columbia culture media, BHI culture media could decline capsular polysaccharide production and mod110 culture media could increase capsular polysaccharide production. While for same culture media, solid culture media was better for capsular polysaccharide production,meanwhile,taken lactose as carbon source could increase capsular polysaccharide production.展开更多
Background:Staphylococcus aureus can cause serious infections by secreting many superantigen exotoxins in“carrier”or“pathogenic”states.HLA DQ and HLA DR humanized mice have been used as a small animal model to stu...Background:Staphylococcus aureus can cause serious infections by secreting many superantigen exotoxins in“carrier”or“pathogenic”states.HLA DQ and HLA DR humanized mice have been used as a small animal model to study the role of two molecules during S.aureus infection.However,the contribution of HLA DP to S.aureus infection is unknown yet.Methods:In this study,we have produced HLA DP401 and HLA DRA0101 humanized mice by microinjection of C57BL/6J zygotes.Neo-floxed IAβ+/-mice were crossbred with Ella-Cre and further crossbred with HLA DP401 or HLA-DRA0101 humanized mice.After several rounds of traditional crossbreeding,we finally obtained HLA DP401-IAβ-/-and HLA DRA-IAβ-/-humanized mice,in which human DP401 or DRA0101 molecule was introduced into IAβ-/-mice deficient in endogenous murine MHC classⅡmolecules.A transnasal infection murine model of S.aureus pneumonia was induced in the humanized mice by administering 2×108CFU of S.aureus Newman dropwise into the nasal cavity.The immune responses and histopathology changes were further assessed in lungs in these infected mice.Results:We evaluated the local and systemic effects of S.aureus delivered intranasally in HLA DP401-IAβ-/-and HLA DRA-IAβ-/-transgenic mice.S.aureus Newman infection significantly increased the m RNA level of IL 12p40 in lungs in humanized mice.An increase in IFN-γand IL-6 protein was observed in HLA DRA-IAβ-/-mice.We observed a declining trend in the percentage of F4/80+macrophages in lungs in HLA DP401-IAβ-/-mice and a decreasing ratio of CD4+to CD8+T cells in lungs in IAβ-/-mice and HLA DP401-IAβ-/-mice.A decreasing ratio of Vβ3+to Vβ8+T cells was also found in the lymph node of IAβ-/-mice and HLA DP401-IAβ-/-mice.S.aureus Newman infection resulted in a weaker pathological injury in lungs in IAβ-/-genetic background mice.Conclusion:These humanized mice will be an invaluable mouse model to resolve the pathological mechanism of S.aureus pneumonia and study what role DP molecule plays in S.aureus infection.展开更多
Objective:To determine the antibiotic resistance profile(ARP)of Staphylococcus(S.)aureus isolates and molecular typing of the methicillin-resistant S.aureus(MRSA)isolates from Tuanku Mizan Armed Forces Hospital(TMAFH)...Objective:To determine the antibiotic resistance profile(ARP)of Staphylococcus(S.)aureus isolates and molecular typing of the methicillin-resistant S.aureus(MRSA)isolates from Tuanku Mizan Armed Forces Hospital(TMAFH),Kuala Lumpur.Methods:The ARP and presence of the pvl gene were determined for 209 S.aureus isolates from clinical specimens.Of these,123 were methicillin-susceptible S.aureus(MSSA)isolates and 86 were MRSA isolates.All MRSA isolates were characterized using SCCmec typing and spa typing.Descriptive analysis was performed to compare the demographic data with the phenotypic and genotypic variables of the S.aureus isolates.Results:No vancomycin-intermediate and-resistant S.aureus(VISA and VRSA,respectively)were detected among the study isolates.The MSSA isolates showed low resistance rates to all tested antibiotics,were commonly invasive(28/42,66.7%),and mostly harboured pvl(35/42,83.3%).Meanwhile,MRSA isolates showed high resistance to penicillin(86/86,100%),ampicillin(86/86,100%),sulbactam/ampicillin(86/86,100%),cefuroxime(81/86,94.19%),cefoperazone(76/86,88.37%),azithromycin(56/86,65.12%),and erythromycin(54/86,62.79%).The majority of MRSA isolates were of SCCmec type IVh(65/86,75.58%),spa type t032(55/85,63.95%),and grouped into spaCC-t022(66/85,77.65%).The t032 type was found to be associated with resistance traits to azithromycin and erythromycin(P<0.05).We also found several spa types that are typically associated with hospital-,community-,and livestock-associated MRSA co-existing in our MRSA population.Conclusions:This study reflected the consistent absence of VISA and VRSA and corroborated the clonal shifting of MRSA isolates in the Malaysian MRSA isolates.展开更多
Objective:To describe clinical and epidemiological characteristics,antimicrobial susceptibility and mortality-associated factors of healthcare-associated infections(HCAIs)caused by Staphylococcus(S.)aureus in children...Objective:To describe clinical and epidemiological characteristics,antimicrobial susceptibility and mortality-associated factors of healthcare-associated infections(HCAIs)caused by Staphylococcus(S.)aureus in children.Methods:We conducted a retrospective,single-centre study of pediatric HCAIs caused by S.aureus from a tertiary care hospital in Turkey between February 2014 and December 2019.The clinical and epidemiological characteristics and antimicrobial susceptibility of the methicillin-susceptible and methicillin-resistant S.aureus(MSSA and MRSA)isolates was evaluated.Results:A total of 310 pediatric patients were examined.Overall,225(72.6%)isolates were MSSA and 85(27.4%)were MRSA.All S.aureus isolates were susceptible to teicoplanin,vancomycin,linezolid,tigecycline,mupirocin,and daptomycin.Penicillin resistance rates were high(89.0%),while fosfomycin,gentamicin,and clindamycin resistance rates were low(1.3%,1.0%,and 2.3%,respectively).Except susceptibility to fosfomycin,which was significantly lower in 2014 compared to 2018 and 2019,no significant difference was found in the antimicrobial susceptibility of S.aureus isolates between the years.Baseline characteristics and mortality rate were similar comparing MRSA and MSSA causing HCAIs.The mortality rate of HCAIs caused by S.aureus was 6.5%(20 patients).Malignancy was an independent risk factor associated with mortality in the multivariate analysis(OR 5.446,95%CI 1.573-18.849).Conclusions:Our findings demonstrate that MSSA remained the most causative agent of HCAIs caused by S.aureus.The mortality rate was 6.5%,the antibiotic resistance rate was quite high for penicillin and diagnosis of malignancy was the main risk factor for increasing mortality in children.These findings could help improve the management of HCAIs caused by S.aureus in children.展开更多
Host-directed therapy(HDT)is an emerging novel approach for treating multidrug-resistant Staphylococcus aureus(S.aureus)infection.Functioning as the indispensable specific cellular receptor for a-toxin(Hla),a-disinteg...Host-directed therapy(HDT)is an emerging novel approach for treating multidrug-resistant Staphylococcus aureus(S.aureus)infection.Functioning as the indispensable specific cellular receptor for a-toxin(Hla),a-disintegrin and metalloproteinase 10(ADAM10)is exploited to accelerate S.aureus infection through diverse mechanisms.The extraordinary contribution of ADAM10 to S.aureus pathogenesis renders it an attractive HDT target for combating S.aureus infection.Our study is the first to demonstrate the indispensable role of ADAM10 in S.aureus-induced necroptosis,and it enhances our knowledge of the role of ADAM10 in S.aureus infection.Using a fluorogenic substrate assay,we further identified kaempferol as a potent ADAM10 inhibitor that effectively protected mice from S.aureus infection by suppressing Hla-mediated barrier disruption and necroptosis.Collectively,our work presents a novel hostdirected therapeutic strategy for using the promising candidate kaempferol to treat S.aureus infection and other diseases relevant to the disordered upregulation of ADAM10.展开更多
BACKGROUND Although neonatal Staphylococcus aureus pneumonia is common and usually curable,it can also be refractory and life-threatening.Herein,we report a case of severe neonatal community-acquired methicillin-resis...BACKGROUND Although neonatal Staphylococcus aureus pneumonia is common and usually curable,it can also be refractory and life-threatening.Herein,we report a case of severe neonatal community-acquired methicillin-resistant Staphylococcus aureus(CA-MRSA)necrotizing pneumonia with bilateral recurrent pyopneumothorax,respiratory failure,heart failure,and cardiac arrest.We hope our report will add to the understanding of this disease.CASE SUMMARY An 18-d-old boy presented with cough for five days,fever for three days,and dyspnea for two days.Preadmission chest radiograph revealed high-density shadows in both lungs.On admission,his oxygen saturation fluctuated around 90%under synchronized intermittent mandatory ventilation.He was unconscious,with dyspnea,weak heart sounds and hepatomegaly.Moist crackles were present throughout his left lung,while the breath sounds in the right lung were decreased.After high-frequency oscillatory ventilation,empiric antimicrobials(meropenem and vancomycin),improved circulation,and right pleural cavity drainage for right pneumothorax(approximately 90%compression),his oxygen saturation level stayed above 95%,and recruitment of the right lung was observed.His condition did not deteriorate until the 5th day of hospitalization(DOH 5).On the morning of DOH 5,his oxygen saturation decreased.Subsequent chest radiograph showed bilateral pneumothorax with nearly 100%compression of the left lung.Desaturation was not relieved after urgent left pleural cavity drainage,and cardiac arrest occurred soon thereafter.Although his spontaneous heartbeat returned through emergency resuscitation and salvage antibacterial therapy(linezolid and levofloxacin)was administered given the detection and antimicrobial susceptibility of MRSA,he showed no improvement,with recurrent pyopneumothorax and continued drainage of purulent fluid and necrotic lung tissue fragments from the pleural cavity.Eventually,his parents refused extracorporeal membrane oxygenation(ECMO)and gave up all the treatments,and the newborn passed away soon after withdrawal on DOH 13.CONCLUSION Neonatal MRSA pneumonia can be refractory and lethal,especially in cases where necrotizing pneumonia leads to extensive lung necrosis and recurrent pneumothorax.Despite treatment with linezolid and other medical measures,it may still be ineffective.Currently,ECMO has been a remedial therapy,but if the lung tissue is too severely eroded to be repaired,it may be useless unless the infection can be controlled and lung transplantation can be performed.Regardless of whether ECMO is initiated,the key to successful treatment is to achieve control over the pneumonia caused by MRSA as soon as possible and to reverse lung injury as much as possible.展开更多
[Objectives]To observe the effects of daphnetin on mastitis induced by Staphylococcus aureus in mice.[Methods]18 postpartum ICR female mice were used to establish mastitis animal model,and were randomly divided into t...[Objectives]To observe the effects of daphnetin on mastitis induced by Staphylococcus aureus in mice.[Methods]18 postpartum ICR female mice were used to establish mastitis animal model,and were randomly divided into three groups(A,B,and C)with 6 mice in each group.Group A:blank control group;group B:S.Aureus model group;group C:S.Aureus model+daphnetin group.The experimental groups were injected 1 mL of 1.0×104 CFU/100μL of S.aureus of along the nipple catheter.The suspension was placed in the 3 rd and 4 th pairs of mammary glands,and the control group was injected with the same dose of normal saline.On the second day after infection,the rats in group A,B and C were given drugs by gavage,while the rats in group A and B were given normal saline and the rats in group C were given daphnetin once a day for 6 consecutive days.Blood samples were collected from living eyeballs,and blood cells were analyzed by automatic flow cytometer after anticoagulation.[Results]The NLR and Systemie Immune Inflammati-on Index(SII)in the blood of mastitis mice induced by S.aureus were significantly higher than those in the control group(P<0.01),suggesting that neutrophil to lymphocyte ratio(NLR)and SII can be used as diagnostic indicators of mastitis,and the levels of NLR and SII decreased significantly after daphnetin intervention.[Conclusions]NLR and SII showed high levels in mastitis mice,which are valuable for the diagnosis of mastitis and the evaluation of its prognosis.After the intervention of daphnetin,both of them decreased significantly,indicating that daphnetin has a good prognosis trend in mastitis mice induced by S.aureus.展开更多
Objective:To evaluate the presence and antibiogram pattern of Salmonella and Staphylococcus aureus(S.aureus)in retail poultry meat products.Methods:Foodborne pathogens(Salmonella and S.aureus)were isolated from poultr...Objective:To evaluate the presence and antibiogram pattern of Salmonella and Staphylococcus aureus(S.aureus)in retail poultry meat products.Methods:Foodborne pathogens(Salmonella and S.aureus)were isolated from poultry meat and confirmed with the help of biochemical and immunological test.Antibiogram of the isolates were examined by following CLS1 methods.Results:A total number of 209 poultry meat samples were collected and studied in this study.Out of which,5.26%were found contaminated with Salmonella while 18.18%were found contaminated with S.aureus.All the Salmonella and S.aureus isolates were found resistant to at least one antibiotic.About 72.72%of the Salmonella isolates showed resistance to tetracycline,while S.aureus isolates were also found highly resistant to tetracycline equal to 44.73%.One of the Salmonella isolates showed multi-drug resistance to almost six antibiotics out of nine antibiotics used in the study.Multidrug resistant S.aureus isolates were also found in the study.Conclusions:The study confirmed the presence of Salmonella and S.aureus in retail poultry meat.It is a potential threat to consumer health.To reduce the risk of contamination,good hygiene practices are necessary from processing to storage.展开更多
A polymerase chain reaction (PCR) assay was employed for direct detection of Staphylococcus aureus without enrichment in dairy products. A solvent extraction procedure was successfully modified for the extraction of...A polymerase chain reaction (PCR) assay was employed for direct detection of Staphylococcus aureus without enrichment in dairy products. A solvent extraction procedure was successfully modified for the extraction of Staphylococcus aureus DNA from artificially contaminated whole milk, skim milk, and cheese. A primer targeting the thermostable nuclease gene (nuc) was used in the PCR. A DNA fragment of 279 bp was amplified. The PCR product was confirmed by DNA sequencing. In this study, the PCR, GB-4789.10-94, Perifilm RSA.Count Plate, and Baird-Parker + RPF Agar were compared. The sensitivity of the PCR was 10 CFU mL^-1 of whole milk, skim milk, and 55 CFU g^-1 of cheese. The developed methodology allowed for detection of Staphylococcus aureus in dairy products in less than 6 h. The time taken for the development of this PCR assay was 12-24 h, less than the time taken by the general PCR assay using the enrichment method, and the coincidence rate of this developed PCR was 94.3%, the sensitivity was 100%. It was a rapid, sensitive, and effective method for PCR to detect Staphylococcus aureus in milk and milk products.展开更多
Objective: To investigate the antibacterial activity of SHHextracted with either water or ethanol against methicillin-resistant Staphylococcus aureus(MRSA) and combinatory antimicrobial effect with ciprofloxacin(CIP) ...Objective: To investigate the antibacterial activity of SHHextracted with either water or ethanol against methicillin-resistant Staphylococcus aureus(MRSA) and combinatory antimicrobial effect with ciprofloxacin(CIP) by time kill assay and checkerboard dilution test. Methods: The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of Sami-Hyanglyun-Hwan(SHH) water extract(SHHW) and SHH ethanol extract(SHHE) ranged from 250 to 2000 μg/m L and 125 to 1000 μg/m L against MRSA, respectively. Results: In the checkerboard method, the combinations of SHHE with CIP had a partial synergistic or synergistic effect against MRSA. The time-kill curves showed that a combined SHHE and CIP treatment reduced the bacterial counts dramatically after 24 h. Conclusions: The present study demonstrates the therapeutic ability of SHHE against MRSA infections.展开更多
This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine...This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and Nhydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine.This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to confirm the conjugation of the targeting ligand via the formation of amide bonds. Approximately 45% of VAN could be loaded into the aqueous cores, whereas 90% DAPT was detected using UV–vis spectrophotometry. In comparison to free drugs, the formulations controlled the release of drugs for > 72 h. Additionally, as demonstrated using CLSM and flow cytometry, the resulting formulation was capable of evading detection by macrophage cells. In comparison to free drugs, red blood cell membrane–DAPT–VAN liposomes, DAPT liposomes, and VAN liposomes reduced the MIC and significantly increased bacterial permeability, resulting in > 80% bacterial death within 4 h. Cytotoxicity tests were performed in vitro and in vivo on mammalian cells,in addition to hemolytic activity tests in human erythrocytes, wherein drugs loaded into the liposomes and RBCDVL exhibited low toxicity. Thus, the findings of this study provide insight about a dual antibiotic targeting strategy that utilizes liposomes and red blood cell membranes to deliver targeted drugs against MRSA.展开更多
基金supported by the National Natural Science Foundation of China (31930106 and U22A20514, U23A20232)the National Key R&D Program of China (2022YFD1300404)+2 种基金the 2115 Talent Development Program of China Agricultural University (1041-00109019)the Pinduoduo-China Agricultural University Research Fund (PC2023A01001)the Special Fund for Henan Agriculture Research System (HARS-2213-Z1)。
文摘Staphylococcus aureus(S. aureus) is a common pathogenic bacterium in animal husbandry that can cause diseases such as mastitis, skin infections, arthritis, and other ailments. The formation of biofilms threatens and exacerbates S. aureus infection by allowing the bacteria to adhere to pathological areas and livestock product surfaces, thus triggering animal health crises and safety issues with livestock products. To solve this problem, in this review, we provide a brief overview of the harm caused by S. aureus and its biofilms on livestock and animal byproducts(meat and dairy products). We also describe the ways in which S. aureus spreads in animals and the threats it poses to the livestock industry. The processes and molecular mechanisms involved in biofilm formation are then explained. Finally, we discuss strategies for the removal and eradication of S. aureus and biofilms in animal husbandry, including the use of antimicrobial peptides, plant extracts, nanoparticles, phages, and antibodies. These strategies to reduce the spread of S. aureus in animal husbandry help maintain livestock health and improve productivity to ensure the ecologically sustainable development of animal husbandry and the safety of livestock products.
基金financially supported by the National Natural Science Foundation of China(82101069,82102537,82160411,82002278)the Natural Science Foundation of Chongqing Science and Technology Commission(CSTC2021JCYJ-MSXMX0170,CSTB2022BSXM-JCX0039)+2 种基金the First Affiliated Hospital of Chongqing Medical University Cultivating Fund(PYJJ2021-02)the Beijing Municipal Science&Technology Commission(Z221100007422130)the Youth Incubation Program of Medical Science and Technology of PLA(21QNPY116).
文摘Background:Treatment of methicillin-resistant Staphylococcus aureus(MRSA)biofilm infections in implant placement surgery is limited by the lack of antimicrobial activity of titanium(Ti)implants.There is a need to explore more effective approaches for the treatment of MRSA biofilm infections.Methods:Herein,an interfacial functionalization strategy is proposed by the integration of mesoporous polydopamine nanoparticles(PDA),nitric oxide(NO)release donor sodium nitroprusside(SNP)and osteogenic growth peptide(OGP)onto Ti implants,denoted as Ti-PDA@SNP-OGP.The physical and chemical properties of Ti-PDA@SNP-OGP were assessed by scanning electron microscopy,X-ray photoelectron spectroscope,water contact angle,photothermal property and NO release behavior.The synergistic antibacterial effect and elimination of the MRSA biofilms were evaluated by 2′,7′-dichlorofluorescein diacetate probe,1-N-phenylnaphthylamine assay,adenosine triphosphate intensity,O-nitrophenyl-β-D-galactopyranoside hydrolysis activity,bicinchoninic acid leakage.Fluorescence staining,assays for alkaline phosphatase activity,collagen secretion and extracellular matrix mineralization,quantitative real‑time reverse transcription‑polymerase chain reaction,and enzyme-linked immunosorbent assay(ELISA)were used to evaluate the inflammatory response and osteogenic ability in bone marrow stromal cells(MSCs),RAW264.7 cells and their co-culture system.Giemsa staining,ELISA,micro-CT,hematoxylin and eosin,Masson's trichrome and immunohistochemistry staining were used to evaluate the eradication of MRSA biofilms,inhibition of inflammatory response,and promotion of osseointegration of Ti-PDA@SNP-OGP in vivo.Results:Ti-PDA@SNP-OGP displayed a synergistic photothermal and NO-dependent antibacterial effect against MRSA following near-infrared light(NIR)irradiation,and effectively eliminated the formed MRSA biofilms by inducing reactive oxygen species(ROS)-mediated oxidative stress,destroying bacterial membrane integrity and causing leakage of intracellular components(P<0.01).In vitro experiments revealed that Ti-PDA@SNP-OGP not only facilitated osteogenic differentiation of MSCs,but also promoted the polarization of pro-inflammatory M1 macrophages to the anti-inflammatory M2-phenotype(P<0.05 or P<0.01).The favorable osteo-immune microenvironment further facilitated osteogenesis of MSCs and the anti-inflammation of RAW264.7 cells via multiple paracrine signaling pathways(P<0.01).In vivo evaluation confirmed the aforementioned results and revealed that Ti-PDA@SNP-OGP induced ameliorative osseointegration in an MRSA-infected femoral defect implantation model(P<0.01).Conclusions:Ti-PDA@SNP-OGP is a promising multi-functional material for the high-efficient treatment of MRSA infections in implant replacement surgeries.
基金supported by Brain Korea (BK)21 Plus Project (4299990913942)funded by the Korean Government,Koreathe Collabo Project funded by the Ministry of SMEs and Startups (C1016120-01-02)the National Research Foundation of Korea (NRF) (2018007551)。
文摘Slightly acidic electrolyzed water(SAEW)has proven to be an efficient and novel sanitizer in food and agriculture field.This study assessed the efficacy of SAEW(30 mg/L)at 40℃on the inactivation of foodbome pathogens and detachment of multi-resistant Staphylococcus aureus(MRSA)biofilm.Furthermore.the underlying mechanism of MRS A biofilm under heated SAEW at 40℃treatment on metabolic profiles was investigated.The results showed that the heated SAEW at 40℃significantly effectively against foodbome pathogens of 1.96-7.56(lg(CFU/g))reduction in pork,chicken,spinach,and lettuce.The heated SAEW at 40℃treatment significantly reduced MRS A biofilm cells by 2.41(lg(CFU/cm^(2))).The synergistic effect of SAEW treatment showed intense anti-biofilm activity in decreasing cell density and impairing biofilm cell membranes.Global metabolic response of MRSA biofilms,treated by SAEW at 40℃,revealed the alterations of intracellular metabolites,including amino acids,organic acid,fatty acid,and lipid.Moreover,signaling pathways involved in amino acid metabolism,energy metabolism,nucleotide synthesis,carbohydrate metabolites,and lipid biosynthesis were functionally disrupted by the SAEW at 40℃treatment.As per our knowledge,this is the first research to uncover the potential mechanism of heated SAEW treatment against MRSA biofilm on food contact surface.
基金supported by the National Natural Science Foundation of China (31972169 and 32001798)。
文摘Staphylococcus aureus is a serious foodborne pathogen threatening food safety and public health.Especially the emergence of methicillin-resistant Staphylococcus aureus(MRSA)increased the difficulty of S.aureus treatment.Staphyloxanthin is a crucial virulence factor of S.aureus.Blocking staphyloxanthin production could help the host immune system counteract the invading S.aureus cells.In this study,we first screened for staphyloxanthin inhibitors using a virtual screening method.The outcome of the virtual screening method resulted in the identification of eugenol(300μg/mL),which significantly inhibits the staphyloxanthin production in S.aureus ATCC 29213,S.aureus Newman,MRSA ATCC 43300 and MRSA ATCC BAA1717by 84.2%,63.5%,68.1%,and 79.5%,respectively.The outcome of the growth curve assay,field-emission scanning electron,and confocal laser scanning microscopy analyses confirmed that eugenol at the test concentration did not affect the morphology and growth of S.aureus.Moreover,the survival rate of S.aureus ATCC 29213 and MRSA ATCC 43300 under H_(2)O_(2) pressure decreased to 51.9%and 45.5%in the presence of eugenol,respectively.The quantitative RT-PCR and molecular simulation studies revealed that eugenol targets staphyloxanthin biosynthesis by downregulating the transcription of the crtM gene and inhibiting the activity of the CrtM enzyme.Taken together,we first determined that eugenol was a prominent compound for staphyloxanthin inhibitor to combat S.aureus especially MRSA infections.
基金financially supported by the National Natural Science Foundation of China(31970137)Sichuan Provincial Administration of Traditional Chinese Medicine Innovation Team Project(2023ZD02)+3 种基金the Scientific Research Fund of Chengdu Medical College(CYZ15-02)the olid-state Fermentation Resource Utilization Key Laboratory of Sichuan Province(2022GTZD02)Natural Science Youth Fund of Science and Technology Department of Sichuan Province(2022NSFSC1760)Sichuan Province College Students Innovation and Entrepreneurship Project(S202113705068,S202213705053)。
文摘Background:Staphylococcus aureus is responsible for the majority of skin and soft tissue infections,which are often diagnosed at a late stage,thereby impacting treatment efficacy.Our study was designed to reveal the physiological changes at different stages of infection by S.aureus through the combined analysis of variations in the skin microenvironment,providing insights for the diagnosis and treatment of S.aureus infections.Methods:We established a murine model of skin and soft tissue infection with S.aureus as the infectious agent to investigate the differences in the microenvironment at different stages of infection.By combining analysis of the host immune status and histological observations,we elucidate the progression of S.aureus infection in mice.Results:The results indicate that the infection process in mice can be divided into at least two stages:early infection(1–3 days post-i nfection)and late infection(5–7 days post-i nfection).During the early stage of infection,notable symptoms such as erythema and abundant exudate at the infection site were observed.Histological examination revealed infiltration of numerous neutrophils and bacterial clusters,accompanied by elevated levels of cytokines(IL-6,IL-10).There was a decrease in microbial alpha diversity within the microenvironment(Shannon,Faith's PD,Chao1,Observed species,Simpson,Pielou's E).In contrast,during the late stage of infection,a reduction or even absence of exudate was observed at the infected site,accompanied by the formation of scabs.Additionally,there was evidence of fibroblast proliferation and neovascularization.The levels of cytokines and microbial composition gradually returned to a healthy state.Conclusion:This study reveals synchrony between microbial composition and histological/immunological changes during S.aureus-i nduced SSTIs.
基金This work was financially supported by Major Science and Technology Project of Yunnan Province(202302AE090022)Key Research and Development Program of Yunnan(202203AC100010)+4 种基金the National Natural Science Foundation of China(32160597,32160236,32371463)National Key Research and Development Program of China(2022YFC2601604)Cardiovascular Ultrasound Innovation Team of Yunnan Province(202305AS350021)Spring City Plan:the High-level Talent Promotion and Training Project of Kunming(2022SCP001)the second phase of“Double-First Class”Program Construction of Yunnan University.
文摘Sensitive detection of Staphylococcus aureus enterotoxin B(SEB)is of importance for preventing food poisoning from threatening human health.In this work,an electrochemical and colorimetric dual-signal detection assay of SEB was developed.The probe(Ab2/AuPt@Fe-N-C)was bound to SEB captured by Ab1,where the Ab2/AuPt@Fe-N-C triggered methylene blue degradation and resulted in the decrease of electrochemical signal.Furthermore,the probe catalyzed the oxidation of 3,3’,5,5’-tetramethyl biphenyl to generate a colorimetric absorbance at 652 nm.Once the target was captured and formed a sandwich-like complex,the color changed from colorless to blue.SEB detection by colorimetric and electrochemical methods showed a linear relationship in the concentration ranges of 0.0002-10.0000 and 0.0005-10.0000 ng/mL,with limits of detection of 0.0667 and 0.1670 pg/mL,respectively.The dual-signal biosensor was successfully used to detect SEB in milk and water samples,which has great potential in toxin detection in food and the environment.
文摘BACKGROUND The oral cavity harbors more than 700 species of bacteria,which play crucial roles in the development of various oral diseases including caries,endodontic infection,periodontal infection,and diverse oral diseases.AIM To investigate the antimicrobial action of Cymbopogon Schoenanthus and Pelargonium graveolens essential oils against Streptococcus mutans,Staphylococcus aureus,Candida albicans,Ca.dubliniensis,and Ca.krusei.METHODS Minimum microbicidal concentration was determined following Clinical and Laboratory Standards Institute documents.The synergistic antimicrobial activity was evaluated using the Broth microdilution checkerboard method,and the antibiofilm activity was evaluated with the 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay.Data were analyzed by one-way analysis of variance followed by the Tukey post-hoc test(P≤0.05).RESULTS C.schoenanthus and P.graveolens essential oils were as effective as 0.12%chlorhexidine against S.mutans and St.aureus monotypic biofilms after 24 h.After 24 h P.graveolens essential oil at 0.25%was more effective than the nystatin group,and C.schoenanthus essential oil at 0.25%was as effective as the nystatin group.CONCLUSION C.schoenanthus and P.graveolens essential oils are effective against S.mutans,St.aureus,Ca.albicans,Ca.dubliniensis,and Ca.krusei at different concentrations after 5 min and 24 h.
基金Supported by the National Natural Science Foundation of China(30771596)~~
文摘[Objective] The effect of different culture conditions on type 5 capsular polysaccharide production of Staphylococcus aureus from diary cattle was studied to provide simple way for CP production and preparation and laid foundation for carrying out new polysaccharide vaccine research. [Method] Staph-ylococcus aureus was isolated from milk sample of sick dairy cattle and capsular polysaccharide serotypes were identified. Type 5 capsular polysaccharide was cultured on BHI,solid columbia and mod110 culture media. Glucose and lactose were taken as carbon sources for every culture media in solid and liquid state. Therefore 9 different culture conditions were taken to study the effect of culture conditions on capsular polysaccharide production. [Result] Different culture conditions indicated that compared with columbia culture media, BHI culture media could decline capsular polysaccharide production and mod110 culture media could increase capsular polysaccharide production. While for same culture media, solid culture media was better for capsular polysaccharide production,meanwhile,taken lactose as carbon source could increase capsular polysaccharide production.
基金National Science and Technology Major Project,Grant/Award Number:2016YFD0500208,2017ZX10304402-001-012 and 2017ZX10304402-001-006Shanghai Science and Technology Commission“R&D public service platform and institutional capacity improvement project”,Grant/Award Number:21DZ2291300Shanghai Public Health Clinical Center projects,Grant/Award Number:KY-GW-2021-39,KY-GW-2019-19 and KY-GW-2019-11。
文摘Background:Staphylococcus aureus can cause serious infections by secreting many superantigen exotoxins in“carrier”or“pathogenic”states.HLA DQ and HLA DR humanized mice have been used as a small animal model to study the role of two molecules during S.aureus infection.However,the contribution of HLA DP to S.aureus infection is unknown yet.Methods:In this study,we have produced HLA DP401 and HLA DRA0101 humanized mice by microinjection of C57BL/6J zygotes.Neo-floxed IAβ+/-mice were crossbred with Ella-Cre and further crossbred with HLA DP401 or HLA-DRA0101 humanized mice.After several rounds of traditional crossbreeding,we finally obtained HLA DP401-IAβ-/-and HLA DRA-IAβ-/-humanized mice,in which human DP401 or DRA0101 molecule was introduced into IAβ-/-mice deficient in endogenous murine MHC classⅡmolecules.A transnasal infection murine model of S.aureus pneumonia was induced in the humanized mice by administering 2×108CFU of S.aureus Newman dropwise into the nasal cavity.The immune responses and histopathology changes were further assessed in lungs in these infected mice.Results:We evaluated the local and systemic effects of S.aureus delivered intranasally in HLA DP401-IAβ-/-and HLA DRA-IAβ-/-transgenic mice.S.aureus Newman infection significantly increased the m RNA level of IL 12p40 in lungs in humanized mice.An increase in IFN-γand IL-6 protein was observed in HLA DRA-IAβ-/-mice.We observed a declining trend in the percentage of F4/80+macrophages in lungs in HLA DP401-IAβ-/-mice and a decreasing ratio of CD4+to CD8+T cells in lungs in IAβ-/-mice and HLA DP401-IAβ-/-mice.A decreasing ratio of Vβ3+to Vβ8+T cells was also found in the lymph node of IAβ-/-mice and HLA DP401-IAβ-/-mice.S.aureus Newman infection resulted in a weaker pathological injury in lungs in IAβ-/-genetic background mice.Conclusion:These humanized mice will be an invaluable mouse model to resolve the pathological mechanism of S.aureus pneumonia and study what role DP molecule plays in S.aureus infection.
基金The study was funded by the UPNM Short Term Grant (UPNM/2019/GPJP/SP/1).
文摘Objective:To determine the antibiotic resistance profile(ARP)of Staphylococcus(S.)aureus isolates and molecular typing of the methicillin-resistant S.aureus(MRSA)isolates from Tuanku Mizan Armed Forces Hospital(TMAFH),Kuala Lumpur.Methods:The ARP and presence of the pvl gene were determined for 209 S.aureus isolates from clinical specimens.Of these,123 were methicillin-susceptible S.aureus(MSSA)isolates and 86 were MRSA isolates.All MRSA isolates were characterized using SCCmec typing and spa typing.Descriptive analysis was performed to compare the demographic data with the phenotypic and genotypic variables of the S.aureus isolates.Results:No vancomycin-intermediate and-resistant S.aureus(VISA and VRSA,respectively)were detected among the study isolates.The MSSA isolates showed low resistance rates to all tested antibiotics,were commonly invasive(28/42,66.7%),and mostly harboured pvl(35/42,83.3%).Meanwhile,MRSA isolates showed high resistance to penicillin(86/86,100%),ampicillin(86/86,100%),sulbactam/ampicillin(86/86,100%),cefuroxime(81/86,94.19%),cefoperazone(76/86,88.37%),azithromycin(56/86,65.12%),and erythromycin(54/86,62.79%).The majority of MRSA isolates were of SCCmec type IVh(65/86,75.58%),spa type t032(55/85,63.95%),and grouped into spaCC-t022(66/85,77.65%).The t032 type was found to be associated with resistance traits to azithromycin and erythromycin(P<0.05).We also found several spa types that are typically associated with hospital-,community-,and livestock-associated MRSA co-existing in our MRSA population.Conclusions:This study reflected the consistent absence of VISA and VRSA and corroborated the clonal shifting of MRSA isolates in the Malaysian MRSA isolates.
文摘Objective:To describe clinical and epidemiological characteristics,antimicrobial susceptibility and mortality-associated factors of healthcare-associated infections(HCAIs)caused by Staphylococcus(S.)aureus in children.Methods:We conducted a retrospective,single-centre study of pediatric HCAIs caused by S.aureus from a tertiary care hospital in Turkey between February 2014 and December 2019.The clinical and epidemiological characteristics and antimicrobial susceptibility of the methicillin-susceptible and methicillin-resistant S.aureus(MSSA and MRSA)isolates was evaluated.Results:A total of 310 pediatric patients were examined.Overall,225(72.6%)isolates were MSSA and 85(27.4%)were MRSA.All S.aureus isolates were susceptible to teicoplanin,vancomycin,linezolid,tigecycline,mupirocin,and daptomycin.Penicillin resistance rates were high(89.0%),while fosfomycin,gentamicin,and clindamycin resistance rates were low(1.3%,1.0%,and 2.3%,respectively).Except susceptibility to fosfomycin,which was significantly lower in 2014 compared to 2018 and 2019,no significant difference was found in the antimicrobial susceptibility of S.aureus isolates between the years.Baseline characteristics and mortality rate were similar comparing MRSA and MSSA causing HCAIs.The mortality rate of HCAIs caused by S.aureus was 6.5%(20 patients).Malignancy was an independent risk factor associated with mortality in the multivariate analysis(OR 5.446,95%CI 1.573-18.849).Conclusions:Our findings demonstrate that MSSA remained the most causative agent of HCAIs caused by S.aureus.The mortality rate was 6.5%,the antibiotic resistance rate was quite high for penicillin and diagnosis of malignancy was the main risk factor for increasing mortality in children.These findings could help improve the management of HCAIs caused by S.aureus in children.
基金supported by the National Natural Science Foundation of China(U22A20523,32172912,and 32102722)the Interdisciplinary Integration and Innovation Project of Jilin University(JLUXKJC2021QZ04)。
文摘Host-directed therapy(HDT)is an emerging novel approach for treating multidrug-resistant Staphylococcus aureus(S.aureus)infection.Functioning as the indispensable specific cellular receptor for a-toxin(Hla),a-disintegrin and metalloproteinase 10(ADAM10)is exploited to accelerate S.aureus infection through diverse mechanisms.The extraordinary contribution of ADAM10 to S.aureus pathogenesis renders it an attractive HDT target for combating S.aureus infection.Our study is the first to demonstrate the indispensable role of ADAM10 in S.aureus-induced necroptosis,and it enhances our knowledge of the role of ADAM10 in S.aureus infection.Using a fluorogenic substrate assay,we further identified kaempferol as a potent ADAM10 inhibitor that effectively protected mice from S.aureus infection by suppressing Hla-mediated barrier disruption and necroptosis.Collectively,our work presents a novel hostdirected therapeutic strategy for using the promising candidate kaempferol to treat S.aureus infection and other diseases relevant to the disordered upregulation of ADAM10.
基金Supported by the Scientific and Technological Project of Shiyan City of Hubei Province,No.21Y32the Medical Research Project of Hubei Pediatric Alliance,No.HPAMRP202114.
文摘BACKGROUND Although neonatal Staphylococcus aureus pneumonia is common and usually curable,it can also be refractory and life-threatening.Herein,we report a case of severe neonatal community-acquired methicillin-resistant Staphylococcus aureus(CA-MRSA)necrotizing pneumonia with bilateral recurrent pyopneumothorax,respiratory failure,heart failure,and cardiac arrest.We hope our report will add to the understanding of this disease.CASE SUMMARY An 18-d-old boy presented with cough for five days,fever for three days,and dyspnea for two days.Preadmission chest radiograph revealed high-density shadows in both lungs.On admission,his oxygen saturation fluctuated around 90%under synchronized intermittent mandatory ventilation.He was unconscious,with dyspnea,weak heart sounds and hepatomegaly.Moist crackles were present throughout his left lung,while the breath sounds in the right lung were decreased.After high-frequency oscillatory ventilation,empiric antimicrobials(meropenem and vancomycin),improved circulation,and right pleural cavity drainage for right pneumothorax(approximately 90%compression),his oxygen saturation level stayed above 95%,and recruitment of the right lung was observed.His condition did not deteriorate until the 5th day of hospitalization(DOH 5).On the morning of DOH 5,his oxygen saturation decreased.Subsequent chest radiograph showed bilateral pneumothorax with nearly 100%compression of the left lung.Desaturation was not relieved after urgent left pleural cavity drainage,and cardiac arrest occurred soon thereafter.Although his spontaneous heartbeat returned through emergency resuscitation and salvage antibacterial therapy(linezolid and levofloxacin)was administered given the detection and antimicrobial susceptibility of MRSA,he showed no improvement,with recurrent pyopneumothorax and continued drainage of purulent fluid and necrotic lung tissue fragments from the pleural cavity.Eventually,his parents refused extracorporeal membrane oxygenation(ECMO)and gave up all the treatments,and the newborn passed away soon after withdrawal on DOH 13.CONCLUSION Neonatal MRSA pneumonia can be refractory and lethal,especially in cases where necrotizing pneumonia leads to extensive lung necrosis and recurrent pneumothorax.Despite treatment with linezolid and other medical measures,it may still be ineffective.Currently,ECMO has been a remedial therapy,but if the lung tissue is too severely eroded to be repaired,it may be useless unless the infection can be controlled and lung transplantation can be performed.Regardless of whether ECMO is initiated,the key to successful treatment is to achieve control over the pneumonia caused by MRSA as soon as possible and to reverse lung injury as much as possible.
基金Supported by Project of Innovation and Entrepreneurship Training Program for College Students in Guangxi Zhuang Autonomous Region in 2022(S202210599060)Basic Ability Improvement Project for Young and Middle-aged Teachers in Guangxi Zhuang Autonomous Region in 2020(2020KY13027)Project of Scientific Research and Technological Development Plan of Baise City in 2020(Encyclopedia[2020]No.47).
文摘[Objectives]To observe the effects of daphnetin on mastitis induced by Staphylococcus aureus in mice.[Methods]18 postpartum ICR female mice were used to establish mastitis animal model,and were randomly divided into three groups(A,B,and C)with 6 mice in each group.Group A:blank control group;group B:S.Aureus model group;group C:S.Aureus model+daphnetin group.The experimental groups were injected 1 mL of 1.0×104 CFU/100μL of S.aureus of along the nipple catheter.The suspension was placed in the 3 rd and 4 th pairs of mammary glands,and the control group was injected with the same dose of normal saline.On the second day after infection,the rats in group A,B and C were given drugs by gavage,while the rats in group A and B were given normal saline and the rats in group C were given daphnetin once a day for 6 consecutive days.Blood samples were collected from living eyeballs,and blood cells were analyzed by automatic flow cytometer after anticoagulation.[Results]The NLR and Systemie Immune Inflammati-on Index(SII)in the blood of mastitis mice induced by S.aureus were significantly higher than those in the control group(P<0.01),suggesting that neutrophil to lymphocyte ratio(NLR)and SII can be used as diagnostic indicators of mastitis,and the levels of NLR and SII decreased significantly after daphnetin intervention.[Conclusions]NLR and SII showed high levels in mastitis mice,which are valuable for the diagnosis of mastitis and the evaluation of its prognosis.After the intervention of daphnetin,both of them decreased significantly,indicating that daphnetin has a good prognosis trend in mastitis mice induced by S.aureus.
基金Supported by University of Balochistan,Quetta,Pakistan(award letter:No.Reg/133/08)the Asian Institute of Technology,Thailand
文摘Objective:To evaluate the presence and antibiogram pattern of Salmonella and Staphylococcus aureus(S.aureus)in retail poultry meat products.Methods:Foodborne pathogens(Salmonella and S.aureus)were isolated from poultry meat and confirmed with the help of biochemical and immunological test.Antibiogram of the isolates were examined by following CLS1 methods.Results:A total number of 209 poultry meat samples were collected and studied in this study.Out of which,5.26%were found contaminated with Salmonella while 18.18%were found contaminated with S.aureus.All the Salmonella and S.aureus isolates were found resistant to at least one antibiotic.About 72.72%of the Salmonella isolates showed resistance to tetracycline,while S.aureus isolates were also found highly resistant to tetracycline equal to 44.73%.One of the Salmonella isolates showed multi-drug resistance to almost six antibiotics out of nine antibiotics used in the study.Multidrug resistant S.aureus isolates were also found in the study.Conclusions:The study confirmed the presence of Salmonella and S.aureus in retail poultry meat.It is a potential threat to consumer health.To reduce the risk of contamination,good hygiene practices are necessary from processing to storage.
文摘A polymerase chain reaction (PCR) assay was employed for direct detection of Staphylococcus aureus without enrichment in dairy products. A solvent extraction procedure was successfully modified for the extraction of Staphylococcus aureus DNA from artificially contaminated whole milk, skim milk, and cheese. A primer targeting the thermostable nuclease gene (nuc) was used in the PCR. A DNA fragment of 279 bp was amplified. The PCR product was confirmed by DNA sequencing. In this study, the PCR, GB-4789.10-94, Perifilm RSA.Count Plate, and Baird-Parker + RPF Agar were compared. The sensitivity of the PCR was 10 CFU mL^-1 of whole milk, skim milk, and 55 CFU g^-1 of cheese. The developed methodology allowed for detection of Staphylococcus aureus in dairy products in less than 6 h. The time taken for the development of this PCR assay was 12-24 h, less than the time taken by the general PCR assay using the enrichment method, and the coincidence rate of this developed PCR was 94.3%, the sensitivity was 100%. It was a rapid, sensitive, and effective method for PCR to detect Staphylococcus aureus in milk and milk products.
文摘Objective: To investigate the antibacterial activity of SHHextracted with either water or ethanol against methicillin-resistant Staphylococcus aureus(MRSA) and combinatory antimicrobial effect with ciprofloxacin(CIP) by time kill assay and checkerboard dilution test. Methods: The antibacterial activity determined by broth dilution method indicated that the antibacterial activity of Sami-Hyanglyun-Hwan(SHH) water extract(SHHW) and SHH ethanol extract(SHHE) ranged from 250 to 2000 μg/m L and 125 to 1000 μg/m L against MRSA, respectively. Results: In the checkerboard method, the combinations of SHHE with CIP had a partial synergistic or synergistic effect against MRSA. The time-kill curves showed that a combined SHHE and CIP treatment reduced the bacterial counts dramatically after 24 h. Conclusions: The present study demonstrates the therapeutic ability of SHHE against MRSA infections.
基金Universiti Kebangsaan Malaysia’s research university grant scheme (DCP-2017- 003/4)。
文摘This study focused on the encapsulation of vancomycin(VAN) into liposomes coated with a red blood cell membrane with a targeting ligand, daptomycin–polyethylene glycol–1,2-distearoyl-sn-glycero-3-phosphoethanolamine, formed by conjugation of DAPT and Nhydroxysuccinimidyl-polyethylene glycol-1,2-distearoyl-sn-glycero-3-phosphoethanolamine.This formulation is capable of providing controlled and targeted drug delivery to the bacterial cytoplasm. We performed MALDI-TOF, NMR and FTIR analyses to confirm the conjugation of the targeting ligand via the formation of amide bonds. Approximately 45% of VAN could be loaded into the aqueous cores, whereas 90% DAPT was detected using UV–vis spectrophotometry. In comparison to free drugs, the formulations controlled the release of drugs for > 72 h. Additionally, as demonstrated using CLSM and flow cytometry, the resulting formulation was capable of evading detection by macrophage cells. In comparison to free drugs, red blood cell membrane–DAPT–VAN liposomes, DAPT liposomes, and VAN liposomes reduced the MIC and significantly increased bacterial permeability, resulting in > 80% bacterial death within 4 h. Cytotoxicity tests were performed in vitro and in vivo on mammalian cells,in addition to hemolytic activity tests in human erythrocytes, wherein drugs loaded into the liposomes and RBCDVL exhibited low toxicity. Thus, the findings of this study provide insight about a dual antibiotic targeting strategy that utilizes liposomes and red blood cell membranes to deliver targeted drugs against MRSA.